1. Field of the Invention
The present invention is generally related to a method for fabricating aerogels, and more particularly to a method utilizing an ionic liquid for fabricating aerogels and their applications in biocomposites.
2. Description of the Prior Art
Aerogel is very light weighted. Aerogel is also called “frozen smoke”, because its density can be as low as 0.003 g/cm3. It is a species of solid with very slim skeleton because its porosity can be as high as 99.9%. The solid is filled with air and thus called “aerogel”. It has a pore network structure and very high specific surface area to hold 1600 times its weight. However, the only drawback is that its structure is very brittle.
Almost all of the applications of aerogel are related to the network structure with porosity higher than 90%. Aerogel has the characteristics of low density, low heat conductivity, low sound spreading speed, low dielectric constant and so forth to become excellent heat-insulating, sound-insulating, electrical insulating materials. It can be used in heat-insulating material, sound-insulating material, electrical insulating material, adsorption material, catalyst, catalyst support, filtering material, dust collecting material, detectors, and capacitors, etc. It can be applied in very broad areas. In addition, it can be applied in the areas of medicine and pesticide as the drug controlled release carrier.
Generally, metal oxide aerogel catalyst is fabricated by using metal alkoxides as a precursor, using sol-gel technique to synthesize wet gel, and then carrying out supercritical fluid extraction and drying. However, the temperature and pressure conditions for supercritical fluid are very harsh. Under such conditions, the activity of the enclosed biomolecule may be destroyed or the enclosed target drug may be extracted and removed. These conditions are not suitable for fabricating biocomposite or bio-wrapping materials. Besides, the procedures for supercritical fluid treatment are very complicated and minute and the operating process may cause explosion. Therefore, a novel method for fabricating aerogel is required to meet the requirements of the industry.